Display "See 'docker cmd --help'." in error cases
Display "See 'docker cmd --help'." in error cases

This brings back this message in case missing arguments.

Signed-off-by: Vincent Demeester <87e1f221a672a14a323e57bb65eaea19d3ed3804@sbr.pm>

Zebrilee/cli,thaJeztah/cli,redpanda/cli,cpuguy83/cli,docker/cli,thaJeztah/cli,allencloud/cli,Zebrilee/cli,dnephin/cli,gdevillele/cli,allencloud/cli,cpuguy83/cli,docker/cli,riyazdf/cli,e11137/cli,redpanda/cli,ashfall/cli,e11137/cli,ashfall/cli,riyazdf/cli,dnephin/cli